Nested router's middleware has no access to request params

[egorovli]

node.js version: 16.2.0
yarn version: 1.22.10
@koa/router version: 10.0.0
koa version: 2.13.1

Code sample:

let usersRouter = new Router()
  .use(async (ctx, next) => {
    console.log(ctx.params.userId ?? 'No user ID in params')
    return next()
  })
  .get('/', async (ctx, next) => {
    ctx.body = {
      id: 1,
      name: 'John Doe'
    }
  })

export let router = new Router()
  .use('/users/:userId', usersRouter.routes(), usersRouter.allowedMethods())

Expected Behavior:

The middleware prints userId to console.

Actual Behavior:

The middleware prints 'No user ID in params' because ctx.params.userId is undefined.

Additional steps, HTTP request details, or to reproduce the behavior or a test case:

This is actually fixed by calling .use() with an empty path 🤷‍♂

let usersRouter = new Router()
  // Here an empty path is used. Previosly it was omitted.
  .use('', async (ctx, next) => {
    console.log(ctx.params.userId ?? 'No user ID in params')
    return next()
  })
  .get('/', async (ctx, next) => {
    ctx.body = {
      id: 1,
      name: 'John Doe'
    }
  })

export let router = new Router()
  .use('/users/:userId', usersRouter.routes(), usersRouter.allowedMethods())

[3imed-jaberi]

I have a quick solution to fix this behave but it's break 2 test case

• Layer > Layer#match() > populates ctx.captures with regexp captures include undefiend:
• Router > matches corresponding requests with optional route parameter:

My Solution:

  // add this line inside the [Router.prototype.use] function just before the hasPath checking.
  if (middleware.length === 1) path = middleware.unshift('');

@miwnwski, what do you think here ?!

[miwnwski]

I actually don't use Koa-router so I have very little insight. @niftylettuce probably has more to say about this than I do I'm afraid.

[niftylettuce]

@3imed-jaberi im open to that 100%

[krosenk729]

following as we have the same issue... is there a workaround or fix for this?